1. Field of the Invention
The present invention relates to a liquid crystal display apparatus and a method of driving a liquid crystal display panel.
2. Description of the Related Art
A liquid crystal display panel comprises a matrix array of pixels each being formed by a switching transistor and a liquid crystal cell. All switching transistors are connected to intersections of column lines and row lines which are successively selected. When one of the row lines is selected, the column lines are respectively driven by write-in voltages. With the advancing technology in the field of flat panel displays, the recent tendency is toward developing large sized, high definition display panels. As the screen size increases, the write-in voltages must travel through the increased length of the column lines. Since the write-in voltages are supplied to the liquid crystal cells of the selected row line for a fixed write-in period, they suffer from undesirable attenuation and distortion, causing different shades of gray to occur between the top and bottom of the screen as illustrated in FIG. 1.
To overcome this problem, Japanese Patent Publication 2002-182616 discloses a technique whereby variable supplemental voltages are generated and combined with write-in voltages. The combined voltages vary increasingly with the distance between the selected row line to the end points where the combined voltages are supplied.
However, because of the analog circuitry, difficulty arises to provide precision circuit adjustment. Therefore, a need exists to provide a solution whereby circuit adjustment can be easily and precisely performed on liquid crystal display apparatus.